What are electrons and how are they involved in creating and electric current?

Electrons are a stable sub atomic particle that has a negative charge and is found in all atoms and is the main carrier of electricity through solids.

In a metal, some of the electrons can escape from the atoms and are free to move around inside the metal. These electrons are referred to as 'conduction electrons'. 

A current is a flow of charge. In metal a current is the flow of the conduction electrons through the metal. This can occur when connected to battery for example: The battery pumps the conduction electrons around the circuit. 

Aform of energy that is reflected or emitted from objects in the form of electrical and magnetic waves that can travel through space. there are many forms of  electromagnetic  energy including gamma rays, x rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves.